feat: enable LSP semantic token highlighting by default

src/plugin.rs

@@ -1,4 +1,4 @@
-use std::path::PathBuf;
+use std::{path::PathBuf, sync::Arc};
 
 use serde::{Deserialize, Serialize};
 
@@ -52,6 +52,59 @@ pub struct Diagnostic {
     pub message: String,
 }
 
+/// Standard LSP semantic token categories, independent of frontend colors.
+#[derive(Clone, Copy, Debug, Eq, PartialEq)]
+pub enum SemanticTokenKind {
+    Namespace,
+    Type,
+    Class,
+    Enum,
+    Interface,
+    Struct,
+    TypeParameter,
+    Parameter,
+    Variable,
+    Property,
+    EnumMember,
+    Event,
+    Function,
+    Method,
+    Macro,
+    Keyword,
+    Modifier,
+    Comment,
+    String,
+    Number,
+    Regexp,
+    Operator,
+    Decorator,
+}
+
+/// Canonical modifier bits; server legend bit positions are translated by LSP.
+#[repr(u16)]
+#[derive(Clone, Copy, Debug, Eq, PartialEq)]
+pub enum SemanticTokenModifier {
+    Declaration = 1,
+    Definition = 1 << 1,
+    Readonly = 1 << 2,
+    Static = 1 << 3,
+    Deprecated = 1 << 4,
+    Abstract = 1 << 5,
+    Async = 1 << 6,
+    Modification = 1 << 7,
+    Documentation = 1 << 8,
+    DefaultLibrary = 1 << 9,
+}
+
+/// A single-line foreground annotation using whole extended-grapheme positions.
+#[derive(Clone, Copy, Debug, Eq, PartialEq)]
+pub struct SemanticToken {
+    pub start: TextPosition,
+    pub end: TextPosition,
+    pub kind: SemanticTokenKind,
+    pub modifiers: u16,
+}
+
 #[derive(Debug, Deserialize)]
 #[serde(tag = "type", rename_all = "snake_case", deny_unknown_fields)]
 pub enum UpdateEffect {
@@ -60,6 +113,13 @@ pub enum UpdateEffect {
         revision: u64,
         items: Vec<Diagnostic>,
     },
+    #[serde(skip_deserializing)]
+    SemanticTokens {
+        buffer_id: usize,
+        revision: u64,
+        /// None clears the overlay. Immutable slices are shared without copying.
+        tokens: Option<Arc<[SemanticToken]>>,
+    },
     Navigate {
         buffer_id: usize,
         revision: u64,